Well, I dont kow what the key is for the reactor placement on the map, but I wonder if anyone else noticed if there are some reactors that have not been marked on the map.

Although the Chernobyl is not operational, as an important source of radioactivity I think it should be marked on the map.

Maybe little unknown, Austria has still operational a small experimental training reactor called Triga - Mark II (250kW thermal), as far as i know located in Vienna, operated by TU Wien - AtomInstitut. Here a link: http://ati.tuwien.ac.at/reactor/EN/